A car navigation device is conventionally equipped with a map search system for retrieving an on-map position that is a position on map data with purposes such as designating a destination. Namely, when a map search system is started by user's input of a search item such as an address, a phone number, a facility name, or the like, an on-map position corresponding to the inputted search item is retrieved on map data. A map around the on-map position is then displayed on a display unit. The user thereby recognizes the on-map position on the displayed map and designates the on-map position as a destination through manipulating a switch.
For the above map search system, the car navigation device possesses search information items that are related to the respective on-map positions. The search information items include an address, a phone number, a facility name, or the like inputted as the search item.
In a car navigation device using map data that covers a wide range of region, the wide range of region is divided into a plurality of search areas. The search information items belong to the respective search areas. Namely, each of the search information items is related to one of the plurality of search areas. Here, when a search item is inputted, within a targeted search area the inputted search item is collated with search information items related to the targeted search area. The reason why a search area for retrieving the on-map position is limited to the single targeted search area is that the number of candidates of the search information items becomes too large if an area for retrieving is expanded to the entire wide range of region.
The above-mentioned targeted search area is typically designated by the user. Once the targeted search area is designated, the designated targeted search area is apt to be continuously retained. Therefore, when a certain search area including a destination is different from the targeted search area, the user needs to switch the targeted search area from the currently designated search area into the certain search area. Here, the user at first determines whether the certain search area is currently designated as the targeted search area. When the certain area is determined to be currently not designated, the user needs to switch the targeted search area from the current search area into the certain search area. This involves user's bothersome procedure for switching the targeted search area in the map search.